1. Field of the Invention
The invention relates to the field of 1,4 substituted piperazines, 1,4 substituted piperidines, and 1-substituted, 4-alkylidenyl piperidines.
2. Summary of the Related Art
Leukotrienes arc potent local mediators, playing a major role in inflammatory and allergic responses including arthritis, asthma, psoriasis, and thrombotic disease. Leukotrienes are straight chain eicosanoids produced by the oxidation of arachidonic acid by lipoxygenases. Arachidonic acid is oxidized by 5-lipoxygenase and ultimately converted to leukotrienes A4, B4, C4, D4 or E4. 15-lipoxygenase is responsible for the conversion of arachidonic acid to various biologically active metabolites including 15-hydroxy-5,8,11,13-eicosatetraenoic acid (15-HETE). Both of these mediators have been implicated in the pathogenesis of airway and allergic diseases such as asthma by contributing to bronchoconstriction, mucus secretion, and eosinophil migration. A mixture of one or more of such leukotrienes are known to be potent bronchoconstrictors. Thus, leukotrienes have been shown to play an important role in the pathology of asthma. Rigorous proof for the role of leukotrienes in asthma has been provided by several pivotal clinical trials in which orally administered 5-lipoxygenase (5-LO) inhibitors (or LTD4 receptor antagonists) produce clear therapeutic benefit in asthma patients. These benefits include reduction in the use of classic asthma therapies such as beta agonists and corticosteroids.
It is well known in the art that certain hydroxyurea- and hydroxyamide-substituted aromatic compounds can function as 5-LO inhibitors. For example, WO 92,09567 and WO 92109566 disclose a wide variety of N-hydroxyurea and hydroxamic acid compounds as inhibitors of the lipoxygenase enzyme.
Histamine has been established to play a role in inflammation in general. Antihistamines are well established most notably for allergy control. Furthermore, histamine is believed to play a role in asthma. For example, histamine and cysteinyl leukotrienes (cLT's) are both known to be key mediators in airway tone. Clinical studies have shown that a combination therapy of a cLT receptor antagonist and an antihistamine administered to twelve asthma patients, reduced early asthmatic responses EAR) and late asthmatic responses (LAR) to a greater extent than either single-acting agent alone (A. Roquet, et al., Am. J. Respir Crit. Care Med, 155, 1856 (1997)). This indicates that histamine plays a role in asthma.
It is well known that certain [bis(substituted and/or unsubstituted aryl) methyl- and methylene]-1-piperidyl compounds possess antihistaminergic activity, and numerous publications disclose such. For example, Yanni et al. (U.S. Pat. Nos. 4,810,713 and 4,950,674) disclose [[bis(aryl)methyl- or methylene-]-1-piperidinyl]alkoxy-aryl and -heteroaryl compounds for the treatment of allergic phenomena, including asthma and rhinitis. Teng et al. (U.S. Pat. No. 5,070,087) disclose [bis(aryl)methyl- and methylene]-N-[(phenoxy and phenylthio)alkyl]piperidines for countering effects of histamine in allergies.
Others have shown [bis(aryl)methyl]piperazin-1-yl compounds for use as antiasthmatics and antiallergics that inhibit leukotriene release (e.g., JP 97077754). U.S. Pat. No. 4,525,358 teaches 2-[4-(diphenylmethyl)-1-piperazinyl]-acetic acid and its amides as antiallergic, spasmolytic, and antihistamine agents. JP 7138230 discloses 4-aralkyl-1-piperazinyl-unsaturated carboxylic acid derivatives useful an antiallergic agents for the treatment of, for example, asthma and rhinitis. WO 97/23466 describes the preparation of N-diarylmethylpiperazines as analgesics.
None of the art, however, teaches, suggests, or contemplates combining the 5-LO and 15-LO inhibiting functionality of hydroxyurea moieties with the antihistaminergic properties of [bis(substituted and/or unsubstituted aryl) methyl- and methylene]-1-piperidyl or -1-piperazinyl moieties in a single entity to yield a compound possessing the dual functions as an antihistaminergic and a 5-LO/15-LO inhibitor.